The Bunch-by-Bunch Feedback System in the MAX IV 3 GeV Ring

The MAX IV facility in Lund, Sweden consists of two storage rings for production of synchrotron radiation. The larger 3 GeV ring has been delivering light to the first users since November 2016, while the smaller 1.5 GeV ring is being commissioned. Coupled-Bunch Mode Instabilities (CBMIs) have been observed in both rings, and they have a degrading effect on the beam quality since they increase the effective emittance and the energy spread. In order to suppress CBMIs, a digital Bunch-By-Bunch (BBB) feedback system has been commissioned in the 3 GeV ring. The feedback in the three planes has this far been two provided by two striplines kickers. A waveguide overloaded cavity kicker, dedicated for feedback in the longitudinal plane, will soon... (More)

The MAX IV facility in Lund, Sweden consists of two storage rings for production of synchrotron radiation. The larger 3 GeV ring has been delivering light to the first users since November 2016, while the smaller 1.5 GeV ring is being commissioned. Coupled-Bunch Mode Instabilities (CBMIs) have been observed in both rings, and they have a degrading effect on the beam quality since they increase the effective emittance and the energy spread. In order to suppress CBMIs, a digital Bunch-By-Bunch (BBB) feedback system has been commissioned in the 3 GeV ring. The feedback in the three planes has this far been two provided by two striplines kickers. A waveguide overloaded cavity kicker, dedicated for feedback in the longitudinal plane, will soon be commissioned. Apart from applying negative feedback, the BBB feedback system is a comprehensive diagnostic tool. The design of the feedback kickers and the implementation of the BBB feedback system in the 3 GeV ring are presented in this report. Initial results from instability studies are also discussed. (Less)

@techreport{b66c6a6b-9d4e-41a0-b015-66ea40889741,
abstract = {The MAX IV facility in Lund, Sweden consists of two storage rings for production of synchrotron radiation. The larger 3 GeV ring has been delivering light to the first users since November 2016, while the smaller 1.5 GeV ring is being commissioned. Coupled-Bunch Mode Instabilities (CBMIs) have been observed in both rings, and they have a degrading effect on the beam quality since they increase the effective emittance and the energy spread. In order to suppress CBMIs, a digital Bunch-By-Bunch (BBB) feedback system has been commissioned in the 3 GeV ring. The feedback in the three planes has this far been two provided by two striplines kickers. A waveguide overloaded cavity kicker, dedicated for feedback in the longitudinal plane, will soon be commissioned. Apart from applying negative feedback, the BBB feedback system is a comprehensive diagnostic tool. The design of the feedback kickers and the implementation of the BBB feedback system in the 3 GeV ring are presented in this report. Initial results from instability studies are also discussed.},
author = {Olsson, David and Malmgren, Lars and Karlsson, Anders},
institution = {MAX-lab, Lund University},
language = {eng},
month = {10},
pages = {53},
series = {Technical Report LUTEDX/(TEAT-7253)/1-48/(2017)},
title = {The Bunch-by-Bunch Feedback System in the MAX IV 3 GeV Ring},
volume = {7253},
year = {2017},
}